Volatile liquid storage tanks operation and system



May 5, 1959 F. E. GILMORE VOLATILE LIQUID STORAGE TANKS OPERATION AND SYSTEM Filed June 12, 1956 N N (Y1 co q-'''ff R a 2 r-" 2 m 0 Z 0 Z Ll-l D- L Q m N i O. 0 Z 3 E 5 a 3,

0 Z 5 INVENTOR. z F.E.GH MORE CL 5 BY United States Patent VOLATILE LIQUID STORAGE TANKS OPERATION AND SYSTEM Forrest E. Gilmore, Bartlesville, 0kla., assignor to Phillips Petroleum Company, a corporation of Delaware Application June 12, 1956, Serial No. 590,856

2 Claims. (Cl. 220-85) This system relates to a volatile liquid storage tanks operation and system. In one of its aspects, the invention relates to a storage tank operation and system having at least two tanks, which are maintained at a predetermined or positive pressure of vapors of a volatile liquid stored in each of them in which operation and system vapors from a tank in which the pressure exceeds a predetermined maximum are pumped by, say, a compressor to a common conduit or zone which is common to tanks of this system and which is maintained at a pressure above said predetermined pressure, or the pressure in any of the tanks, and from said common zone, as needed, to another tank in which the pressure has fallen below a predetermined or positive pressure of vapors due to pumping out of liquid or other reason, for example, cooling at night. In an important modification, a liquid trap zone is provided in communication with said common zone to separate from vapors any liquid present or formed therein. The liquid is passed to one of the tanks in the system under the pressure maintained in said common zone. This liquid may be formed due to increase of pressure upon the vapors and/or to cooling of the compressed vayors. There is provided in one embodiment a source of vapors extraneous to the system for passing vapors into said common zone whenever the overall supply of vapors to said zone from said tanks is insuificient to maintain said common zone at a predetermined minimum pressure of vapors. Also, in one embodiment, there is made provision for releasing vapors from said common zone whenever the pressure therein exceeds a maximum predetermined pressure. In a preferred embodiment of the invention, the operation is completely automatic based upon certain aspects and concepts as described, upon other aspects and concepts among which are included operation of vapor pumping zones automatically responsive to tank pressure and vapor to tank feed zones also automatically responsive to tank pressure including certain interpositioning of vapor flow control or check zones, and upon aspects and concepts as will appear from the following:

It is an object of the invention to provide a volatile liquid storage tanks operation and system. Another object is the provision of an operation in which all tanks are protected against drawing in outside atmosphere, or air, or drawing a vacuum. Another object of the invention is to provide an automatic method and means for maintaining a plurality of tanks at a predetermined maximum pressure in each. A still further object of the invention is to provide for the utilization or removal from the storage tanks of vapors in excess of that required to render the operation effective, as desired. Another object is to provide for a source of vapors with which to supply sufficient vapors for the operation and system at those times when the system does not contain sufficient vapors, for example, on a cold day or at night. Other objects are apparent from this specification, the appended claims and the drawing, in which there is illustrated diagrammatically an embodiment of the invention composed of ICC three tanks. One skilled in the art in possession of this disclosure will realize that for sake of simplicity only a sufficient number of details and component parts are shown to describe the invention and its underlying concepts to him.

Referring now to the drawing, 1, 2 and 3 are storage tanks in which a volatile liquid, for example, a hydrocarbon such as gasoline, is stored. Tank 1 is standing, that is, nothing is being pumped into or out from the tank. It is storing gasoline. Tank 2 is receiving gasoline and tank 3 is being pumped out and is, therefore, sending gasoline, say to a gasoline blending plant, market, etc. Tanks 1 and 2 are connected by equalizing line 4 and this line is connected to compressor 5 by way of line 6. Compressor 5 is operative responsive to the pressure in equalizing line 4 as indicated by the broken line 7, switch 8, motor 10 and drive shaft 11. Switch 8 is a pressure responsive switch, which in this embodiment, is set to shut off compressor 5 when the pressure in line 4 is approximately 0 inch of water and to place compressor 5 into operation whenever the pressure in line 4 reaches approximately 3 inches of water. The vapors from compressor 5 when it is in operation pass by way of line 12, check valve 13, block valve 14 (open when the system is in operation), line 15 into line 16. Lines 15 and 16 are in communication with lines 17 and 18, leading to liquid traps 19 and 20. Also, lines 15 and 16 are in communication by means of valves 21 and 22 in lines 23 and 24, respectively, with equalizing line 4 and tank 3. Lines 23 and 24 are in open communication with common conduit lines 15 and 16 at 15A and 16A, respectively. Since equalizing line 4 is in open communication with'tanks 1 and 2, all three of the tanks can receive vapors through valves 21 and 22, which, in this embodiment, are adjusted to open only when the pressure downstream of the valves in lines 23 and/or 24 has fallen to a pressure below atmospheric of approximately %1 inch of water or below. Substantially as described in connection with tanks 1 and 2, which are connected by way of equalizing line 4 and line 6 with compressor 5, tank 3 is connected by way of line 24 and line 25 with compressor 26. Compressor 26 is adjusted by means of broken line 27, switch 28, motor 29 and drive shaft 30 to be responsive to the pressure in tank 3 and will be operative when the pressure in tank 3 exceeds approximately 3 inches of water and will cease operation when the pressure in said tank has been reduced to about 0 inch of water. As described in connection with compressor 5, compressor 26 discharges into a line 31 equipped with a check valve 32 and a block valve (open when the system is in operation) and through the block valve into line 16. Line 16 is provided with outflow back pressure controller valve 34 and inflow pressure controller valve 33. Valve 34, in this embodiment, is adjusted to allow vapors from line 16 whenever the pressure therein is in excess of approximately 18 p.s.i.g. to flow to a gasoline recovery plant, not shown. Whenever the pressure in line 16 falls to below approximately 3 p.s.i.g., valve 33 will open to admit natural gas from a source not shown into line 16.

From the foregoing, it will be obvious to one skilled in the art in possession of this disclosure that a completely automatic operation and system have been set forth and described permitting a plurality of tanks to be maintained under a predetermined or positive pressure regard less of whether the tanks are merely standing, receiving or sending and further regardless of variations in temperature which occur each day.

Certain modifications of the system will become apparent to one skilled in the art studying this disclosure. By way of modifications which are already shown in the drawing, can be mentioned pressure relief valves P at mass, 109

the top of each 'Thesevalves can be so constructed as'to admit outside atmosphereintdthe' tanks in the event of a power failure or other occurrence necessitating momentarily the admission of outside atmosphere into one or more tanks .to prevent their collapse due to too 1 high a vacuum. Ofcourse,va1ves"'P:are' adjusted to 'prevent excessivewpressures on each ta'nk;:usuallyi the safe working pressnrvof the tank; which for' cone 'roof tanks 'ranges from. 2 inches to 6 inches of water pressure. '.This'ipre- "determined pressure in this embodiment isapproximately 1% inches or water pressure.

modifications are possible and, in the drawing, shown return lines 35 and36 which areeguipped ,withhow check valves'37 and 38,"respectively. These linestreturn liquid which'has'been trappedont inttraps L19 aiid'flltotanks 2 and 3, respectively. Of course,the liquid can be returned to other tanksin the'system'z'or, in (tact, toanyother place in the' storage'field.

,Not shown on.the' drawing but by'wayoffurtherxmodi- 7116350 1; '19 and can be equipped "with cooling mils or fins orotherwise positioned to receive a'co'oling tatmosphere such astfurnished' bya fan orra waterspray. "In such event, the vapors will be considerably're'duced by condensationof liquid therefrom, and may, in some instances, be completely condensed.

ilt is believed clear that valves 121 and Rare open only at a time when'compressors 5 and 26are not in service. Flowicontrol or vcheck valvesv 37 and "38will notbe operative when thepressure inline l6'and, there- "fore, I9 and 20 notjgreaterthanthepressure .in lines 35:0.nd 36, re'spectively.

"'Wltilethe invention has beendescribedin aispecific embddimentthereof withrespect to a specific example in gasolineiis being stored, received orpumped'from re spectiveftanksofthe system, it'will beclearthiattdit- 'ferenttfi'actions or'volatile materials can'bestored in ltflflerenrtanks long 'as theirvaporscanrbe acceptably \irith'each 'o'ther. [I'Inthe event "the vapors can- "tiotbe'atirrlixed "eachwi'th' the "other, suitable surge'areas With sealscanbe providedto avoid suchadmixture.

Reasonable variation and modification are possible within'the scope of the foregoing, disclosure, drawing and :the appended claims to'the invention the essence of which lie that therefihas been provided a volatile.liquidstorage tanks operation and system, as described, wherein each or the tanks of the systemlautomatically is. maintained '4 above a predetermined minimum pressure and wherein a common zone of vapors'is provided from which vapors are automatically supplied tanks requiring the same to maintain the pressure in the said tanks and from which common zone also liquid from the vapors is removed and sent to storage as desired also as described.

I claim:

-I. -A-storage tank system whichcomprises a E plurality of tanks, a vapor line connectedtoeach'of said tanks and to a compressor respectively, a conduit means connecting said compressor to a common vapor lconduit common to each of'said tanks and to a vapor'recoverysystemrespectively, :pressure responsive control it means responsive to pressure in at least one of said tanks to render said compressor operativeto'removevapors from one of said tanks whenever the pressure therein is above a predetermined maximum and to compress vapors therefrom into said common vapor:conduit aconduit connecting each of said tanks with said common vapor-wconduit means responsive .tolthe pressurein eachnoflsaid tanks operativetopermit fflowrflirough l said last-mentioned conduit from. said com- .mon vaportconduithintolthestank vto whichrsaid-i last-menltioned conduit is-connec ted whenever the pressure in said llast-mcntioned tank falls below a predetermined minimum, and .means responsive to the pressure in it said common vapor conduit adapted 'to control flowwof vapor ,from .said recovery systcminto said common vapor con- ..duit whenever the pressure therein falls below alpre- .determined. minimum which is: above 7 the maximum, pressure in any of said tanks. and to release vapors from said common vapor conduit rtorsaid vapor "recovery system whenever the,.pressure "inlsaid scommon vapor conduit texceedsta predetermined maximum.

.2. A systemt-according tmclaim 1 whereinsaid com- "moo vapor -conduit =.is provided with-a liquid trap -means .arrangedrto trap liquid'fromthercompressed' vapors thereinland wherein :aconduit connects said liquid trap to I at ileast oneof saidtankstoperniitflow 'oftliquid only from .said trap to said last-mentioned tank.

References Clted in the file of this patent UNITED STATES PATENTS 1,701,870 Ccmraderv 1Feb.. 12, (1929 1,794,383 Laird. Mar. 3,:1931 =1,901,576 Atwellt Mar. 14,1933 72,682,752 Branson ..:July6,19S4 

